Paint spray gun



April 1, 1952 A D1 STEFANO 2,590,848

PAINT SPRAY GUN Filed Aug. 25, 1948 3 Sheets-Sheet l N um MMIII.

N 4b N Q Q i. n

l a Albert D155 no en* ATTORNEY A. Dl STEFANO PAINT SPRAY GUN April l, 1952 V5 Sheets-Sheet 2.

Filed Aug. 25, 1948l mm E ATTORNEY A. Dl STEFANO PAINT SPRAY GUN April 1, 1952 3 Sheets-Sheet 3 Filed Aug. 25, 1948 ATTOR N EY Patented Apr. l', 1952 UNITED star -FFICE 2,5%',848 PAINT SPRAY GUN Alberoni` stefano, Philadelphia; Pa. Applicata@ August 25, 194s, serial No. 461Mo (ci. a99- 122) 14'r Claims. 1 l

This invention relatesv generally to improvementsin spray guns and is directed particularly to an improved nozzle attachment fora paint spraygun. Y

A principal object of the present invention is toprovide amdevice for attachmenttol any ordi nary type of paintspray gun; whereby the pattern of the spray projected `from thel gun can be'controlled and' by means df which a substan tlally fogless paint'strearri' or spray is produced;

Another objectof thevinvention is to provide an attachment for the nozzle end of ay paint spray gunfwhich is constructed and arranged inga novel rn'anr'ierV whereby the air ejected with the spray is 'completely separated and deflected away from thegpaint droplets whereby the'formation of mist orV fog is completely avoided;

A further and important object of the present invention is to provide in anattachment for the nozzle' of a spray gun, an element which functions in accordance with the' law of aero-#dy-V namics known as Bernoullis law, to deflect the air and lighter mist particles' from Vthe paint spray whereby aperfectly` clean or air free fogless spray is projected forwardly andthe air is carried off through ltering elements.

Still anotherohject of the invention is to provide a device of the character described whereby new artistic effects are made possible in sign painting and decorating and inV otherfpainting projects by reason of the factwthatithe'device functions to produce a'spray infr which the droplets of paint are'alll of the same uniform size. n

Other objects and advantages ofthe invention will become apparent as the description of the saine' proceeds and the invention will be best understood from a consideration of the following detailed description taken in connection with the accompanyingdrawings forming apart of the' specication, with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obviousy modifications will occur to a person skilled in the art.

Inthe drawings:

Figure 1 is a view partly in top plan and partly in horizontal section of a device constructed in accordance with the present inventionv thesame being shown attached to a' standard'type of paint spray gun.

.Figure2 Ais'a sectional view taken substantially onthe line 2-2 of Figure 1.

Figure 3 is a' view infront elevation of the device', parts' beingfbro'ken-away.

`Figure 4 isa sectional viewv taken substantially on an` enlarged scale through the modied nozzlestructure.

Figure 2 shows in side elevation a cominontype' of spray gunin connection with which thepresent invention is used. In this gun the handgrip is designated Eil' and' hasA leading to and through it-l an air passage; not shown, which communi-jn cates with the couplingv'Il at the lbottoml end of the hand Vgrip where Van air hoser isf connected. The numeral I2V` designates the paint receptacle connection for thegunwhile the controlitri'g'ger is designated I 3 and functions to open` thefair line whereby to discharge air through-A thef passage I in the*` headl, see Figure 5, andv4 out at the nozzletip Iii. d d l d The* numerals IjI and I8 designate thufnb screws which respectively control theair Howto the hereinafter described' Venturi-jets and paint flow, the screw IT adjustingl the position or theA air valve stem I9 while thcscrew` I8 adjlus'tsv'the position of the painty control needleyalve 2li.`

In accordance'with the present invention the common internal atomizing nozzle-is replaced by the modined nozzle here vshown and' generally designated 2| whichnozzle issecur'edfto the gun head by the threadedcoupling ring 21a" in the forward end of whifchthenozzle'tip is seuredin the manner illustrated.y

Connected with the nozzle'l to receive air therefromare the four outwardly and rearwardly curving jet tubes 221 each of which has its outlet end or tipflattened as indicated at 23" to forma atair jet which is directed rearwardly. d

Secured in position upon the gun head by the locking ring 2`Ia,` as is clearly illustrated infFfige' ure 2, is a circular plate 24 which has formed integral therewith the" relatively wide collar 25. This plate has anY opening 26' in* its center to receive the portion of the'gun head'uponwhich the ring 2 Ia isv threaded and in orderto maintain the plate 24y firmly'in position there ist Apl'a'td" behind it and in encircling relation withV theV` portion of the gun extendingthrough theoper r ing 25, the collar 211 Thus' it Will-'beseen that when'the coupling vring 2id isthreaded'ontofth gun head it will press the plateV 24j firmly against the collar 2l to secure the plate in position.l

The plate 2I`hasv the two arcuate `openi`ngsf28 formed therein with their major proportions above the"horizontal plane" of theV nozzle, 'as shown in' Figure 4 and integral with theplate 24 andlead ing rearwardly from each of these openings 28 is a Venturi-tube 29. These Venturi-tubes are spaced apart slightly as shown in Figure 1 to receive between them the finger hook 30 which forms a part of all spray guns and which assists in properly positioning or centering the device upon the gun head.

For the proper support of the Venturi-tubes there is provided a bracket plate 3| which is secured as a bridge across between the tubes 29 and which is provided with a slot or recess 32 to receive the portion of the gun head through which the air valve extends and mounted upon the stem of the air valve and secured firmly in position by the air valve 33, is a hook 34 which engages in the aperture 35 of the Venturi bracket and thus prevents any tendency for the Venturi-tubes to move upwardly or to prevent them from being forced upwardly in a manner which might tend to damage the plate 24 of which they form a part.

- lThe back edge of the Venturi-plate collar 25 has formed integral therewith the relatively narrow forwardly directed flange 36 which forms a forwardly opening channel around the collar or around the perimeter of the plate 24. The purpose of this iiange and channel will be hereinafter set forth. y

Detachably coupled with the Venturi-plate co1- lar 25 is the hollow circular head which is generally designated 31. This hollow head has a front wall 38 which curves upwardly and rearwardly to form the encircling side wall 39, the latter terminating in the rearwardly directed annular rim 4B which is of an inside diameter to receive the collar 25 somewhat loosely, for the purpose hereinafter described.

The front Wall 38 has formed therethrough the substantially elliptical spray outlet opening 4|, the long axis of which is disposed transversely of the gun in the illustrations here given but it may be disposed at any angle desired but is always maintained in the plane of the spray discharge slot 42 of the tip I6, which slot as shown in Figures 3 and 4 is relatively long and narrow.

The nozzle tip has the flattened surfaces 43 which parallel the length of the slot 42 and this portion of the tip fits into the correspondingly shaped opening 44 which is formed in the center of the back wall 45 of a rearwardly tapering air bale or hood 46. This hood at its forward end is of a width corresponding to or slightly greater than the width of the spray discharge opening 4| and the forward end of the hood is of a height slightly greater than the height of the opening 4| asl shown in Figure 2. As is also shown in this figure the forward end or edge of the hood is defined by a flange 41 which bears against the inner side of the wall 38 of the head and is secured thereto by screws 48. It will thus be seen that the hood covers at the top and sides the space lying between the nozzle and the outlet opening `4| but the lower part of the hood is open.

Secured to the lower half of the wall 39 of the head 31, adjacent to the rim thereof and by means of rivets 49 is a substantially arcuate drain baille plate 50, the top concave edge of which has the upwardly and rearwardly extending fingers which support the curved or arcuate wire 52 which constitutes a filter guard. This bafile encircles thelower half of the nozzle as is clearly shown in Figures 2 and 4.

The numeral 53 designates a cloth lter which is in the form of a bag and which is secured at its edge to a rim gasket 54 which may be formed of cardboard or any other suitable material. This bag has an opening 55 therein through Which the nozzle tip extends, when the filter bag is in position, as shown in Figure 2.

The filter bag is placed in position by placing the gasket 54 on the Venturi-plate collar 25, at which time the nozzle tip will be extended through the filter bag opening 55 in the manner illustrated.

In oider to maintain the lter bag in the desired position within the head there is provided a filter bracket which is generally designated 56 and which comprises a split ring 51 which has attached to the upper half thereof by means of the forwardly and inwardly converging arm portions 58, the arcuate frame 59. As will be readily seen upon reference to Figure 2 the split ring 5| is located within the mouth of the bag at the inner edge of the gasket 54 and the arcuate frame 59 which follows the contour of the upper half of the split ring. is extended forwardly into the bag. After this assembly has been made and the gasket has been placed in position on the collar 25 the rim of the head is applied to encircle the gasket as shown and this rim is split as indicated at 60, in Figure 1, and carries at the opposite sides of the split, the upstanding ears 6| which are connected by a screw 62, whereby the ends of the split may be drawn together to contract the rim around the gasket and collar.

As will be readily seen upon reference to Figure 2, when the head is placed in position the filter guard 52 will press the lower part of the filter bag rearwardly into the circular space defined by the Venturi-plate collar 25 while the upper half of the bag will be held forwardly over the hood 46 and away from the air jet nozzles 22. The numeral 63 designates a shutter for the spray discharge opening 4|. As shown most clearly in Figure 3 this shutter comprises the relatively wide plate 64, the width of which is substantially equal to or slightly greater than the width of the opening 4| and the height of which plate is slightly greater than the height of the opening. l

Extending laterally and curving rearwardly from the lower left hand corner of the plate 63, as viewed from the front of the device, is a hinge arm 65 which is pivotally joined by the pivot member 66 to the side wall of the head 31 adjacent to the rim of the head.

At the opposite side of the head from the pivot member and in line therewith, the wall of the head is provided with an aperture 61 through Which extends a portion of an operating lever for the shutter. generally designated 68. This lever comprises a relatively long inner end or shank portion 69 which is attached to an arm 10 which corresponds to the hinge arm 65, and an outer spring finger member or terminal portion 1| which has the friction tip 12 which bears against the adjacent wall of the head. This contact between the tip 12 and the wall of the head is relatively firm or tight so that when the shutter is oscillated by manipulating the finger portion 1| and has been set in the desired position, the frictional contact will hold the shutter in such position.

It will be readily seen upon reference to Figures 2 and 3 particularly that the shutter can be lowered to a position where its top edge is below the bottom edge of the outlet opening 4| or it can be raised to partially close the opening or to completely close it if desired.

The numeral 13 generally designates an air defiector. This air defiector comprises a central body portion a which in cross section, as shown in Figure2, is substantially ovate. This body portion, as shown inV Figure 3 is relatively long mis-designed or adapted. to lie across the rear part oifthe'a'ir` baiiie 46 below r` the.1 openingv 42101 the nozzle. I6'.

The body of the air: denector atl the` opposite ends,r thereof merges with the forwardlydivergin`g arms 11i.' which are pivotallyattached` as at4 14 tothe opposite. sides of"l the` baflie 46 incl'ose proximity' to the rear or innerV side of the: shut terl.A

The body-portion a: ofthe air. deiiector is recessedat therear top sidethereof as indicated at candlthe long. axis of the. bodyextends downwardlyandforwardly andn at the larger end of the. ovalz there is ixedin the: body'the:` plugl 'l5 in which is. threaded an end of' an adjustment screw,V '16.` This screw extends downwardly; and forwardly through theA bottom part of the: side wall of the head and, outside of" the head 31 the screwv carries: the knurled head l1 by means of which; it may be rotated so as to slightly elevate or' lower the air.' deilector as may be desired.

Therecessc in the. rear top side of theair de-i eotor body receivesr the lower part. of the projecting portion of the nozzle and thev part of the baille in` which the nozzle is enclosed so that the forward rounded surface of the body of the air4 deiiector leadsv downwardly and forwardly from just below the; outlet opening 42 of the nozzle. Accordingly it will be seen that the proxirnityof` this surface particularly at the highest point" thereof; can be increased or decreased with respectto the lowerv sideof the nozzle outlet 42- to regulate the iniiuenceof the curved surface. of the-air: foil upon the air stream is- The side. wallof the filter enclosing head 3T isfprovided with the several circumferentially spaced drain openings. 18. A drain tube 19 is provided for` engagement at one end into one of these openings 'I8 asv shown mostv clearlyl in Figure 2, the other openings beingl closed by suitable plugs 80.

In the use of the present device the reversed air'ow through the twin Venturi-tubes 29 receives most of its force from the energy in the frontair jet producing the paint spray. The air ejected forwardly with the spray possessescon siderable momentum and in passing over the downwardly curved top surface of the air deiiector it will tend to curve downwardly in accordance with the effect defined by Bernoullis laws.,

. The airv ejected forwardly with the spray is separated bythis action from the paint spray andisturned downwardly into the lower part of the head unit and passes backwardly and upwardly through the lter cloth to and through the openings 28 leading to the rearwardly directed Venturi-tubes. Thus this reversal of iiow of the air stream separated from the paint stream combines with and forties the rearward iiow induced by the air jets or Venturi-jets 22.

The space between the shutter 63 and the adjacent part of the front wall of the unit head, andlthef forward lower part of the air deflector isV considerably narrower than the space between the .under side of the air foil and the bottom part of the head wall so that as the air passes down around y,the Aair deflector a further venturi eii'ect islobtained and this action causes some air to be pulled in through the opening 4| across the bottomedge thereof, .bythe low pressure created Vby the air deiiector and the venturi eiectv inthe space between the air deector and the shutter.

The spray and airv arev separated by.- this action Inaddition-to the filter cloth, therspace around the baie 46 and beneath the-air deflector may be and preferably is lledrwith stranded-metal such asi steelwool,l fiber glass orthol like which catchesand retains most of' the fog orn'e paint which: may-. be carried down byv the air, after which' the air vpasses' through: the-'iiltering` cloth where the il'ast of the paint is completely ree movedL from the.y air. This removedY paint drains tothe-bottom ofthe head-.and passes out through theV tube 19 to a suitable receptacle,

The Venturil jetsact asboostersto accelerate the'movement, of the air rearwardly through the ltering media. i

By the action of this gun attachmentgpei'- fectly clear air is ejectedA from the back of the unit while completely foglesspaint spray is shot out through the mouth or opening 4|. This fogless, fanned spray is so completely free of disturbing air currents thatfit can'be cut down-in crossv section by the employment of the shut'- ter G3.

The droplets are arranged in the form of a massspectrograph and it is possible to block out any part of the mass spectrum thatis not wanted leaving sprayed droplets of all they same` uniform size. This feature makes new artistic effects possible in sign painting and decoratingetc.

All liquid caught inside the unit drains down. as stated, to the bottom to be carried 01T bythe tube 19 to be caught and reused. The head may be rotated on the supporting Venturi plate collar as previously described so as to obtain a-fan lying in any plane from vertical to horizontal and whenv such change is made the drain tube 1'9 will be shifted o'rchariged to' oneo'f the other drain openings so' as to always lead' from the bottom part of the head.

Since the nozzle tip I6 ts, as previously stated, into a non-circular openingV in the back of the baiiie, thetip will rotate withrespect to the nozzle portion'2l thus turning as a unit with the attachment or `front assembly, this turning of the tipwith the front assembly being made possibleby loosening'the wing screw 62 aspre# viousl'yl stated.

As previously described the air deiiector 13 is pivotally mounted' on the pivot members 14 and is adjustable uparid down by means ofthe screw or stem T6. This adjustment has the effect of increasing ordecreasing theV air' deflection angle to' get the best results withY the different"y air pressures.

Another purpose of'l the shutter 63 is' to prevent the lower lip'oi' the mouth opening 4l from getting wet with paint. The fshutter getswet and the paint runs down into the-inside ofv the unit rather thanA running down theV outside' ofV the headl from'the lower edge of theV mouth 4l.

I claim:

1. In a paint spray gun having a nozzle pro.- vided with a jet tip, an attachment having a hollow head having a front wall provided with an outlet opening, means for mountingv said head on the nozzle with said openingin position for the forward discharge.v of the,y jet tiptherethrough. rearwardly-l directed ain. outletsextending.1 from 'and an outlet for draining olf the said deflected `portion of the spray jet Yfrom said head discharge through said rearwardly'directed outlets.

2. A structure of the character set forth in claim l, with filtering means within the head between the said space through which a portion of the spray jet passes and the said rearwardly directed outlets. -f 3. A structure of the character described in claim 1 with means within the head for filtering the said portion of' the spray jet to eect separation of air from' paint, means for draining oif separated paint from the lower part of the head, and blowing means for forcing movement of the air through the rearwardly directed outlets.

4. An attachment for a paint spray gun -comprising a nozzle having a rotatable spray tip, a plurality of jet nozzles' carried by said nozzle to receive air therefrom and directed rearwardly, an enclosure for said nozzle and jet nozzles comprising a circular plate mounted upon the spray gun behind the first nozzle and having o utlet openings lthrough which the jet nozzles are directed, a hollow head, connecting means between the peripheries'of the head and the plate to allow the turning of the head on the axis of the nozzle tip, said of the tip, a filtering element partitioning the said enclosing means between the head and the back wall plate, an air deiiector disposed transversely of and in close proximity to the nozzle tip, said air deflector having a forwardly and laterally curving surface disposed in front of the tip in a positionvto have a jet issuing from the tip pass over such surface, there being a space between said air deiiector surface and the front wall of the head -for the passage of a portion of vthe spray-jet into the lower part oi the head, said jet nozzles functioning to facilitate rearward movement of a part of the said portion of the spray jet, and drainage means for the lower part of the head.

5. A structure of the character set forth in claim 4, with means mounting said air defiector for movement relative to the nozzle tip, and means for effecting the adjustment of theair deiiector `correspondingly for variations in the rate of discharge from said tip.

6. A structure of the character set forth in claim 4, with a pivotally mounted shutter for movement across the said outlet opening of the head, and means disposed upon the outer' side oi the head and connected through the head with the shutter for facilitating movement of the shutter and for maintaining the shutter in adjusted position relative to the head opening.

7. A paint'spray gun structure of the character stated in claim 4 wherein the said connection between the front wall 0f the head and the nozzle tip comprises a hood having a top portion and depending side portions, and said air deector being disposed in the lower part of the hood be- 8 tween said side portions and pivotally mounted for adjustment relative to the nozzle tip, and means extending outwardly of the head and for adjusting said deector relatively to said nozzle.

8. A paint spray gun structure of the character stated in claim 4 wherein the said connection between the front wall of the head and the nozzle tip comprises a hood having a top portion and depending side portions, and said air defiector being disposed in the lower part of the hood between said side portions and pivotally mounted for adjustment relative to the nozzle tip, and means mounted in the front wall of the head and connected with the air deiiector for adjusting the air deflector relatively to said nozzle, and a shutter pivotally mounted within the head for vertical oscillation within the hood and across the outlet opening of the head.

9. A spray gun construction of the character stated in claim 4 wherein the said filtering means comprises an armular frame encircling the nozzle and contacting at its outside periphery against the inner surface of the head, a filter cloth encircling said annular frame and having a central opening through which the nozzle tip projects, and a gasket of circular form secured to the edge of said cloth and held between thejoining portions of the head and said back plate.

l0. An attachment for a paint spray gun having a fanning valve, comprising a nozzle having a spray tip, a plurality of jet nozzles carried by said nozzle to receive air therefrom, the jet nozzles being positioned to discharge air rearwardly away from the tip, means for adjusting the air supply head having a forward Wan provided with an r to said jet nozzles being controlled by the gun anning valve, and an enclosure for the first nozzle and the jet nozzles including a circular plate mounted upon the gun behind said rst nozzle and having outlet openings through which the jet nozzles are directed, the enclosure having a forward opening through which the spray tip is directed.

1l. The combination with a spray gun havinga nozzle provided with an outlet through which a jet of air and substance propelled thereby is ejected, of a hollow head encircling said o utlet and having a front opening in line therewith, and means for effecting separation oi air from the substance after issuance of the jet from the outlet comprising a body of elongated arcuate form supported within said head, said body having a rounded surface disposed adjacent to said outlet and immediately below the same to have the jet pass closely thereover, the said body surface curving forwardly and downwardly from the path ol travel of the jet.

12. The combination as set forth in claim 11, with means extending through the front wall of said head below the opening therein for adjusting the said body relative to said outlet to accord with different velocities of the jet.

13. In a paint spray gun having a nozzleand a jet tip, an attachment having a hollow head having a front wall provided with an outlet opening, means for mounting said head on the nozzle in position for discharge of said jet tip through said opening, means within the head for deflecting a part of a spray jet issuing from the tip away from said opening into a part of the head, means for removing the deflected part of the spray jet by a way other than the outlet opening, and means for varying the area `of the said outlet opening to reduce the dimensions of the spray pattern passing therethrough.'

14. The combination with a spray gun having 9 a nozzle provided with an outlet through which a jet of air vand substance propelled thereby is ejected, of a hollow head encircling.r said outlet and having an opening in line therewith, a relatively long air deflector of arcuate form disposed within the head below said outlet with the ends of the dei-lector directed forwardly in straddling relation with the lower part of the head opening, said deector having a forwardly and downwardly curving top surface in close proximity to the lower side of the nozzle outlet, pivots coupling the ends of the deector to the head for oscillation of the deflector on an axis extending transversely of the head, and means connected with the deflector for moving the same on said pivots to change the position of said curved top surface relative to the nozzle outlet.

` ALBERT DI STEFANO.

REFERENCES CITED The following references are of record in the Afile of this patent:

UNITED STATES PATENTS Number Name Date 853,787 Henry, Jr May 14, 1907 1,803,967 Good May 5, 1931 1,828,463 Hammers Oct. 20, 1931 1,920,721 Tirrell Aug. 1, 19'33 2,256,080 Eweryd et al Sept. 16, 1941 2,270,579 Chamberlin et al. Jan. 20, 1942 

